Drive unit and projector attachments for planetarium projectors

ABSTRACT

A drive unit and interchangeable projectors form moving or stationary light spots of variable size and intensity simulating astronomical images in planetaria, includes a base frame having a plurality of apertures to receive removable projectors, a geared electric motor including means for transmitting rotary and other motions to the projectors, and electric current connections for the illumination of the systems of the rotary projectors including means for maintaining the current for the projectors during rotation.

United States Patent [72] Inventor James D. Vickery 2,748,652 6/1956 Bauersfeld et a1. 35/425 670 Garland St., Lakewood, Colo. 80215 3,388,484 6/1968 Kiffer 35/425 UX g; 1 gppg. No. 32.113019 FOREIGN PATENTS l e Paemed Jam 29. 1971 399,078 9/1933 Great Britain 353/94 Primary Examiner-Jerome Schnali Attorney-Richard D. Law [54] DRIVE UNIT AND PROJECTOR ATTACHMENTS FOR PLANETARIUM PROJECTORS ll Claims, 17 Drawing Figs.

U-S. A drive unit and interchangeable projectors 29/00 form moving or stationary light spots of variable size and ini i Search tensity simulating astronomical images in planetaria, includes a base frame having a plurality of apertures to receive removable rojectors, a eared electric motor including means for [56] Rem-mm cued transmitting rotars and other motions to the projectors, and UNITED STATES PATENTS electric current connections for the illumination of the 1,542,120 6/1925 Widre 35/425 X systems of the rotary projectors including means for maintain- 2,693,130 1 1/1954 Green 35/425 ing the current for the projectors during; rotation.

PATENTEU JUH29 IHYl SHEET 2 OF 8 INVI'IN'IOR. James D. Vickery ATTORNEY PATENTEH JUN29 ISYI SHEET 3 OF 8 INVIEN'IUR. James D. Vickery AT TORNE Y PATENTEH JUN29 mm SHEET LL 0F 8 FIG. 8 lNVlfN'l'UR.

James D. Vickery ATTORNEY PATENTEUJUNEQIBYI 3 5 9 035 SHEU 5 BF 8 FIG. I/

INVIL'NTUR.

BY James D. Vickery ATTORNEY PATENTEuJuuzeisn 3,589,035

INVI-IN'I'UR.

James D. Vickery zz/wag? ATTORNEY PATENTEUJUN291971 SHEET 8 OF 8 INVIL'N'IY )R.

James D. Vickery BY ATTORNEY DRIVE UNIT AND PROJECTOR ATTACHMENTS FOR PLANETARIUM PROJECTORS Planetaria are synthetic displays of celestial bodies, demonstrating a relation of one another, movements of said bodies in relation to each other, and in one particular movement in relation to the earth. Planetaria are normally buildings having a dome-shaped auditorium, and a principal projection mechanism calledan orrery, which projects spots of light on the hemispherical ceiling of the building simulating celestial bodies and their movement. Various lighting effects will produce simulated lightening, aurora, and the like, all of which is intended for the entertainment and the education of the viewing public. The planetarium, or orrery, can not alone, however, demonstrate certain phenomena visually observable from the earth or demonstrate such phenomena as is speculated by the scientist as occurring under different conditions in time and space. The orrery is the basic tool for the planetaria, and it is almost indispensable for a complete program display. According to the present invention, I provide what might be considered an aid to the orrery capable of producing a number of different simulated phenomena, and which is relatively inexpensive and quite easy to adjust and operate. The unit consists of a basic frame member into which one or more of a seriesof projectors may be attached; the base unit providing circulatory and/or oscillating movement of the projectors as well as the electric current for lighting the projector lamps. The base unit includes means for holding one or more of such projectors to produce a series of celestial image phenomena. The base unit provides the power gearing and electrical current support for the projector attachments. The basic unit is equipped with a transformer and a set of outlets for each pro jector support so as to provide either high voltage or low voltage depending uponthe requirements of a specific projector attachment. Remote control of the unit is easily provided through the switches and Variacs so that the unit may be placed at a distance from the control center of the planetarium. By providing an individual projector attachment with cams, scrolls, eccentric gearing or reduction gearing, a variation of orbital speed for the individual projectors is easily obtained. An important feature is that the projector attachments are quickly and easily assemblied with or disassembled from the base unit and these are nominally held by spring loaded clamps. The structure of the projector attachments is such that many common parts are used in all of the projectors decreasing the cost of the combined unit.

Included among the objects and advantages of the present invention is a planetarium aid for projecting a variety of images of celestial phenomena on the dome of a planetarium.

Another object of the present invention isto provide a base unit arranged to accept one or more of a series of auxiliary projectors, providing electrical service for the projectors and necessary orbital movement of the projector and/or parts thereof for producing the desired effect.

A further object of the invention is to provide a base unit for a planetarium aid'which is arranged to accept one or more auxiliary projectors, provided with a motor and power train for inducing movement to a projector or projectors mounted therein.

A still further object of the invention is to provide a planetarium aid which includes a base unit for supporting a series of auxiliary projectors each of which includes a substantial number of components common to all of the projectors, including a base for mounting projectors in said basic unit and means for connection of the projector into a power train in the base unit.

These and other objects and advantages of the invention may be readily ascertained by referring to the following description and appended illustrations in which:

FIG. I is a side elevational view, in section, ofa base unit for holding one or more projectors, according to the invention;

FIG. 2 is a top plan view of the device of FIG. I;

FIG. 3 is a perspective view ofa modified base unit, according to the invention, for holding from one to three auxiliary projectors;

FIG. 4 is a cross-sectional view of one form of a projector according to the invention with a slide holder;

FIG. 5 is detailed view of the slide holder of the projector of FIG. 4;

FIG. 6 is cross-sectional elevation of a projector having an occulting screen;

FIG. 7 is a cr'oss'sectional view of the projector of FIG. 6 taken along section line 7-7 showing a spiral track for movement of the occulting screen;

FIG. 8 is a cross-sectional elevational view of a modified projector which includes a mirror for changing the angle of projection;

FIG. 9 is a detailed view of slide holder for the projector of FIG. 8;

FIG. 10 is a cross-sectional elevational view of an auxiliary projector arranged to project a spot of light in an elliptical orbit upon the domed ceiling of the planetarium;

FIG. I] is a top plan view of an elliptical track for supporting the auxiliary projector of FIG. 10;

FIG. 12 is a detailed elevation of the projector holder of FIG. 11-,

FIG. I3 is a cross-sectional elevational view of an auxiliary projector for simulating a rising sun;

FIG. 14 is a perspective view of the projector of FIG. 13;

FIG. 15 is a cross-sectional view of a double projector system for illustrating twin stars;

FIG. 16 is side elevational view, partially cut away, of a modified projector for showing an aurora display on a domed ceiling ofa planetarium; and

FIG. 17 is a side elevational view, partially cut away, of an idler gear for one form of the base unit according to the invention.

In the device selected for illustration in FIGS. 1 and 2, a base unit according to the invention includes a hollow circular frame 10, constructed of a ring of light material such as aluminum, magnesium, etc., having a bottom 12 secured thereto and enclosing the same, and a perforate top I4 secured to the opposite end of the tubular frame 10. A series of adjustable legs or feet 15 are secured to threaded bolts 16 which extend through the bottom 12 into the hollow space in the frame 10 and a nut 17 provides means for leveling the frame. The feet are preferably covered with a rubber or plastic foot for stability on slick surfaces and to soundproof the unit in its operation. A series of four or moreof the legs are preferred for stability of the unitin its operation. The unit must be quite stable since the base is arranged to support a series ofprojectors which project images on a ceiling across a substantial distance and any wobble in the unit is magnified by the projection. Mounted internally of the shell 10 and attached to the top I4 is an electric motor 20 having a shaft 21 extending through the top 14 andjournaled in bearing set 22 supporting a pair of gears 23 and 24 extending above the unit. A transformer 25 is secured to the bottom of the base housing and a series of leads; not shown as they are conventional, extend to terminals 27a and 27b secured to receptacles 28 and 29 which extend through'and are accessible from the top 14. An electric supply line 30, which may be a conventional AC supply passes through an opening in the shell 10 to supply power to the transformer 25.

The top 14 of the unit is perforated by holes 33a, 33b and 33b arranged around the periphery of the unit and a hole 33d,

generally centrally, all located in the top. These holes 33a,

33b, and 33c extend completely through the top and are arranged to receive a static base portion of projectors. Spring clamps 34 mounted on bolts 35 and biased by a spring 36 provide means for retaining a projection in the particular opening. As explained below each projector has a collar with the flange which prevents the'projector from passing completely through the opening and positions the projector in the opening. Each spring clamp pivots about the bolt 35 to leave an uninhibited opening and permit entry of the projector unit into the hole. The clamp pivots back to seat over the flange and securely holds the projector in the top. A series of three double outlets are provided for the openings in the top, and each of the series includes two female receptacles. These may be for knife blade male or round male prongs on plug of the projector. One of the receptacles, for example number 28, provides 6 volt direct current (6 v. DC) from the transformer while the other receptacle 29 provides 110 volts alternating current (llO v. AC) to provide versatility in the type of projector which may be used with the base. in the projection of various astronomical phenomena it may be desirable to utilize a projector having a 6 volt system, which is usually preferable since the heat produced from the lamp is considerably less. However, in other cases it may be necessary to use a larger bulb for greater light intensity from the projector, and the 1 10 volt outlet provides means for accommodating such a projector using the higher voltage. As will be explained below, each of the projectors arranged to be inserted into the base is provided with an electric line which can be plugged into one of the receptacles. By providing the receptacles with different types of plugs it will be impossible for a low voltage projector to be attached to a high voltage plug thereby providing a safety feature.

The electric motor 20 is preferably a synchronous low r.p.m. motor, and the gearing mounted on the motor shaft is preferably a silent type gearing since such projectors are operated for a noiseless crowd. The connecting gears 23 and 24 are usually rotated at l r.p.m. As will be explained below, each of the projectors for moving images is provided with a gear and as is shown in FIGS. 6,7,8, l0, 13, M, and 16, each moving image projector mounted on the base unit has gears which mate directly (or through intermediary idler gears) with one of the gears 23 and 24. The lower gear 23 is mounted concentrically on the shaft to provide engagement with a mating gear on a projector or idler gear mounted in the opening 33d. A gear 24 is mounted cccentrically on the shaft 21 to mate with an eccentrically mounted gear on a projector or idler gear to provide an elliptical type of movement. Under normal circumstances where a single projector is used it will be mounted in the opening 33d with its gear meshed with either gear 23 or 24. Different rotational effects may be provided by inserting an idler gear in the opening 33d and placing one or more projectors in one or more of the peripheral openings, as for example, where two projectors are being used they may be placed in openings 33a and 330 with the idler gear in 33d rotating both of the projectors. An idler gear and mount is shown in FIG. l7, wherein a stationary base 37 is provided with bearing sets 38 supporting a shaft 39 on which is mounted a gear 40 having mating teeth for either of the gears 23 or 24. Normally. the idler gear is a concentrically mounted gear for providing rotation to the projectors mounted on one of the peripheral openings. The base 37 of the idler gear is provided with a peripheral flange 37a which seats on the top member 14 positioning the gearing in properly and providing securing means by the spring clamps 34.

As explained, the base unit is equipped with a transformer and the receptacles for different voltages, depending upon the requirements of the specific attachment. Remote control of the projectors may be readily provided through the uses of switches and variable power sources connected between a control console and the unit, depending upon the desires of the user. For variation in speeds each individual projector attachment may be equipped with cams, scrolls, eccentric gears or reduction gears as may be desired.

A slightly modified version of the base is illustrated in FIG. 3. wherein a tubular frame 42, provided with legs 43 similar to those of FIG. I, is provided with the bottom cover 44 and a top cover 45. The top cover 45 is provided with openings 46a, 46b and 460 arranged near the periphery around the top cover 45. Each opening is provided with adjacent electrical receptacles 28 and 29 and spring clamps 34 for securing projectors in the openings. The motor, however, is not rigidly secured to the top cover but is mounted to a slide in a slot 47 so that a gear 48 mounted on the motor shaft may be moved toward and away from the opening 46b, for engaging the gears of the projector which is placed in any of the openings in the top. Therefore, when a geared projector is placed in one of the openings 46a, 46b, or 46c, the motor may merely be slid along slot 47 until gear 48 engages the gear of the geared projector. This unit provides versatility in having different sizes of gearing which may be selectively used on a projector for changes of speed etc. Also, as illustrated in FIG. 3, a power line 50 provides power to the transformer into the 110 plugs, a switch line 51 provides means for turning the unit on or off as desired from a control console, and a powerline 52 to a Variac provides means for controlling the intensity of the light from the projectors. The two base units are otherwise generally operated in a similar manner.

A typical projector is illustrated in FIG. 4, which projectors of the stationary type, and this includes a lower tube 50 provided with a base 51 supporting a lamp socket 52 and a lamp S3. A flanged sleeve 54 with its flange 55 is arranged to rest on the top of the top cover 14 and support the projector in any of the openings 33. As pointed out above, the spring clamps secure the projector in the base by the clamp extended over the flange. A pair of lenses 56 and 57 are secured in the tube 50 and provide a part of the optical projection system. An upper tube 58 is threadedly attached to the lower tube 50 by means of an adapter 62, and this upper tube includes lenses 60 and 61 to complete the lens system. The threaded adjustment of the upper section with the lower section provides means for focusing the image on the domed ceiling. The adapter includes a rectangular slide holder having a slide entrance opening 63 (FIG. 5) and the adapter is secured between the upper and lower section. This provides means for inserting a transparent slide therein for projecting an image on the ceiling of the planetarium. This slide holder may be provided with a slide tray in accordance with conventional practice or it may be merely a slot for supporting a conventional transparency or one mounted in glass. Leads 64 and 65 for the electric circuit for the lamp may be passed back through the tube 50 above the flange 55 and with a male plug on the end be arranged to be inserted into one of the female receptacles for illuminating the lamp S3.

A modified version of the projector of FIG. 4 is illustrated in FIGS. 6 and 7, which is an eclipse projector for either a lunar or solar eclipse. This projector includes a lower tube system 50, which is similar to the lower tube system of FIG. 4, and an upper system 58 which is similar to the tube system of FIG. 4. in place of the slide holder 62, however, this eclipse projector is provided with an adapter which includes an occulting screen for projecting an eclipse. When arranged as a lunar eclipse projector, it is provided with a transparent slide 72, which is an actual photograph of the moon. The occulting screen includes a disc 73 having a central aperture 74 mounted in the adapter 70. An occulting screen 75 is pivoted by means of a pivot pin 76 in the adapter 70 in position to slowly cover the aperture 74. End arm 77 of the occulting screen has a cam follower 78 secured to the outer end thereof. The cam follower is arranged to be mounted in a. spiral groove 79 in a gear 80 which is mounted on an idler base 37 such as shown in FIG. 17. The idler base 37 is secured to the lower tube 50 by means of a connector 81 to provide a complete unit. For attachment of the device to the base, the idler fits in the central aperture 33d and the projector fits in one of the other apertures 33. The gear 80 mates with the gear 23. Initially the follower 78 is placed in the outermost point of the spiral groove 79 to maintain the aperture 74 fully open. When the projector is turned on, the image of the moon is projected on the ceiling of the planetarium, and when the motor is turned on to actuate the gears, the occulting screen 75 moves slowly across the aperture simulating an eclipse of the moon. By making the occulting disc 75 ofa copper color and translucent enough to simulate the umbral stage of a lunar eclipse, a very realistic representation of an eclipse of the moon is projected on the ceiling. An adjustment on the disc, that is by moving it inwardly or outwardly of the aperture, will allow a partial or total eclipse of the moon to be simulated. The arm 78 attached to the oceulting screen is spring steel so that it may be lifted and reset in the position in the scroll or spiral grooves 79.

The attachment shown in FIGS. 6 and 7 may, also, be used for a solar eclipse where the slide 72 is removed and replaced with a transparent slide photograph of the sun. A second straight projector, as shown in FIG. 4, is placed in one of the other openings in the base, as two projectors are used with the sun or solar eclipse. The second projector is equipped with an actual photograph of the suns corona during an eclipse. The solar eclipse simulation is started by operating the electric motor, to start the occu'lting screen over the aperture 74, and by the use ofa variable transformer the light of the projector with the oceulting screen is made to fade out, while the light of the stationary projector with the slide of the corona is increased in intensity until the point where the oceulting screen completely covers the aperture 74 where it is turned off and the corona projector is turned full on to simulate the full eclipse of the sun. The sequence is then reversed for the retreat of the moon from the sun in the solar eclipse.

The projector of FlGS. 8 and is for demonstrating rotating galaxies, and this includes a rotating projector 85 mounted on a stationary support 86 for inserting in opening 33 in the base unit. The projector 85 includes a lower tube and lamp arrangement with its lens system thereabove and a slide tray 87, for insertion of an actual photograph of a galaxy, and the upper lens system, all of which is more or less conventional. The projector has a gear 88 attached thereto, and the projector is mounted on a shaft 89 for rotating in the journals 90 mounted in the adapter 86. The shaft 89 is hollow and leads 91 and 92 pass from the lamp down through the shaft and is attached by means of connectors to contact strips 93 and 94 mounted on the outside of a drum 95 secured to the shaft.

Brushes 96 and 97 connected respectfully to leads 98 and 99 provide means for bringing current to the lamp on rotation, the brushes riding on the contact strips 93 and 94. Power leads 100 pass through the adapter 86 to the connections 98 and 99, and a plug on the end of the lines, not shown, being arranged for insertion into the female receptacle, being either 6 or 1 volt depending upon the application. A brace plate 101 is secured to the adapter 86 and it supports a mirror stanchion 102 which supports a mirror 103 mounted by a pivot pin 104 to a rotary insert 105 mounted in the stanchion 102. The mirror 103 may thus be pivoted around the pivot pin 104 and rotated in the stanchion 105 to project the image at essentially any place desired on the ceiling of the planetarium.

Where one or more rotating galaxies are desired a number of such projectors may-be inserted in the openings in the base and by adjusting the mirrors the rotating galaxies can be placed in any position on the ceiling. In some instances it may be desirable to have two projectors with the adjustable mirrors and a static projector such as shown in H6. 4. These projectors were designed to allow a discussion of the nature of the galaxies and to allow a hypothetical trip into space. The galaxy projector includes a transparency slide mount 89, as shown in FIG. 9, and it provides a tray 107 which slides in the opening and this tray supports a slide in accordance with conventional practice. A handle 108 provides easy insertion or withdrawal into the slide holder.

An elliptical orbit projector is provided in the device of FIGS. 10 and 11, and this includes a flanged adapter 110, which is arranged to seat in an aperture 33 in the top plate 14 of the base and is held in position by spring clamp 34. A rotary shaft 111 is journaled in bearing sets 112 in the adapter base 110 supporting an elliptical gear 113 which is arranged for connection with either an idler gear or the elliptical gear of the motor. The shaft 111 is hollow and leads 114 extending thereto to a lamp in a projector. A projector 116 is pivotally mounted on a yoke 117 by means of pivot pins 118 on each side to pivotally support the projector 116. The projector is spring biased by spring 119 one side ofthe gear 113. A vertical mount 120 secured to a connector mount 121 extending form the adapter supports an elliptical track 123. The elliptical track 123 is mounted by a bolt 124 on a lug 125 movably secured to the upright by means ofa headed bolt 126 ex tended through a slot 127 in the upright 120. The bolt 126 provides means for a height adjustment of the track 123 in the slot and, also, the lug permits the track to be turned at an angle thereto for changing the configuration of an ellipse in relation to the projector. A lamp 125 is supplied with current through the leads 114 which are attached to conductor strips 128 on which ride brushes 129 to provide continuous contact with current from leads 103 which pass through the adapter 111 to the brushes 129. A plug, not shown, on the ends of the leads 130 provides connection into the female receptacles in the top of the base. When mounted in the central opening 331! in the base, the elliptical gear 113 engages the eccentric gear 24 for the movement of the projector 116. Since the projector is biased by means of the spring in one direction against the track, rotary movement of the projector causes it to move in an elliptical path and the projected image moves in an elliptical path across the ceiling of the planetarium.

The elliptical projector is designed to demonstrate the behavior of orbiting bodies, and Kepler's Law can be specifically treated. The projector is, also, useful for showing movement of comets and the like. The elliptical gearing on the attachment provides for a speedup and slowdown during the orbiting movement of the projector in keeping with Kcplers Law of areas to provide speed change at the foci of the elliptical path. The elliptical harness or track 123 guides the projector in its elliptical path. The harness may be raised and lowered in the guide slot on the upright which changes the size of the elliptical path, and by rotating the harness about its horizontal axis it provides a different shape ofellipse.

The projector shown in FIGS. 13 and 14 demonstrate a rising sun. This unit includes a stationary projector arranged for mounting in an opening in the top plate 114 of the base with its flange seated on the top in the manner of the other projectors. lts upper tube 136 attaches to the base portion 135 through a slide adapter 137 secured therebetween. The series of colored discs 138 are mounted in the upper projector portion, and a variable iris 139 is mounted in the adapter below the discs. A screen 140 with an oval aperture is, also, mounted in the adapter to provide for projecting a sun image which is oval, and is explained below. An iris opening drive 141, which includes a push rod 142 for opening and closing the iris, has a cam follower 143 mounted on its end 141 which rides in a spiral path cam 144 (similar to the cam of FIG. 6) mounted on a gear 145 on an idler adapter 146. A mirror is mounted on yoke arms 151 attached to an upper section 136 of the projector and a tilting arm 152 is attached to the mirror. The tilting arm rides in a yoke 153 mounted on the gear 145. As the gear turns the iris is opened and the rod 152 is pulled around by the yoke raising the mirror to raise the image from an initial horizontal position toward a zenith on the ceiling.

The rising sun attachment demonstrates the effects of atmospheric refraction, the physiological phenomenon of exaggerated, apparent size of the sun on the horizon, and provides a beautiful planetarium sunrise. The sun image first appears oval, red and large due to the color discs mounted in the upper projector section and the open iris. The oval shape of the first appearance of the sun is provided by an elliptical hole in the image plate. The three colored discs are provided in the upper section with holes of different sizes and these are located out of focus in the light path to provide the color changes on closing movement of the iris. The iris is driven by the cam which changes from large opening to a small opening. As the iris contracts, it cuts out the oval image to project a smaller size of sun which gradually becomes round. With further contraction the outer red color disc is cut out of the path smoothly revealing an orange color. The iris contracts further to accommodate the yellow disc only and by this time the image is small, yellow and round. All the time the iris is contracting, the mirror 150 is moving to project the image from the lower edge of the ceiling shown as a horizon toward the zenith to give the effect of the rising sun. A simple screen, as between the mirror and the wall, may be provided to cut out the sun image at the horizon line so that the image is not seen on the chamber wall.

A double rotating projector, shown in FIG. 15, is useful for illustrating a binary star system, and this includes an adapter 160 for fitting in one of the openings in the top plate 14 of the base, which adapter includes bearing set 161 for rotatably holding a rotary shaft 162 which is hollow to permit lines 163 to pass therethrough. The lines are connected to rotary contacts 165, similar to those shown in the other projectors, which rotate with the shaft to provide current form leads 166 through the brushes to the rotary contactors. Mounted on the top of the shaft is gear 167 which is arranged to mesh with the gear on the motor. A U-shaped bracket 170 is mounted thereon with its arms extending upwardly. A pair of projectors l7] and 172 are pivotally mounted by means of pivot pins 173 to the U-shaped bracket 170 which permits the projectors to pivot toward and away from one another. Each projector may be arranged at a particular angle so that the two images appear to rotate about each other on the ceiling of the planetarium.

A cove galaxy projector or an aurora projector is illustrated in FIG. 16, wherein an adapter 180, similar to the adapters of the other projectors, is arranged to be mounted in an opening 33 in the top of the base 14, and this includes a rotary electrical connector system 181, similar to the rotary contact systems of the other projectors. A shield 182 is mounted in stationary position on a cover 183 which is connected to the adapter 180. The cover includes a slit 183 through which image projections may be made. A gear 184 is secured to a ro tary shaft 185 to which is attached a rotary drum 186. The rotary drum is attached to head 187 secured to a shaft 185, and arranged to rotate therewith. A lamp 188 is mounted on the shaft for rotation with the drum 186. At the opposite end, an electrical rotary connector 189 is mounted on a shaft 190 to provide means for supporting another lamp inside the drum (not shown) in a manner similar to that of the described end. The shaft 190 passes through a stationary adapter 191 which is mounted on a support 192 connected to a yoke 193 which is mounted on a cover 183 of the unit. Leads for both lamps are arranged with plugs on the end for connection with the female receptacle in the base unit. The drum 186 is transparent and covered with several hundred galaxy images preferably from actual photographs, and the drum is made opaque except for the images which are projected by lights from the lamps passing therethrough. In using the device, the base unit is set up horizontally instead of vertically in the cove of the planetarium, so that the drum 186 rotates horizontally. The shield is turned so that there is no projection below the horizon. As the drum turns at about 1 rpm. the images rise slowly from the horizon as though they were radiating from a single point and they increase in size as they approach the zenith.

Various other celestial phenomena may be made using the base with slight variations in the projectors. Each is easily assembled and set for showing. Obviously, the configuration of the base may be changed, by those skilled in the art, and be within the concepts of the invention.

lclaim:

l. A projection system for planetaria comprising a base inclusive of a frame supportable on a supporting surface; a planar member on an upper portion of said frame having a series of apertures therein; a motor mounted in said frame having its shaft protruding above said planar member; at least one gear mounted on said shaft above said member; power supply means on said frame for said motor; a series of rotatable projectors selectively attachable to said base by telescoping in an aperture of said series of said apertures, and all projectors of said series of projectors having similar bases for insertion into an aperture of said series of apertures; gear means mounted on each projector of said series of projectors for rotative association with said at least one car on said shaft for rotatin each said projector concentricafiy about the aperture of sai series of apertures in which said projector is mounted; and means for connecting the lamp of each projector to said power supply means.

2. A projection system according to claim 1 including spring clamp means on said frame for temporarily securing projectors of said series of projectors thereon.

3. A projection system according to claim 1 wherein a pair of gears are mounted on said shaft, one above the other, and each gear of said pair provides means for meshing with a gear on a projection of said series of projectors.

4. A projection system according to claim 1 wherein the apertures of said apertures are spacedly arranged for mounting a projector of said series of projectors in each aperture of said series of apertures at the same time.

5. A projection system according to claim 1 wherein each aperture of said series of apertures is circular and said bases of said projectors are circular.

6. A projection system according to claim 1 including outwardly directed flange means depending from each said projector for supporting said projector on said planar member.

7. A projection system according to claim 6 wherein said outwardly directed flange means is an annular flange for seating on said planar surface.

8. A projection system according to claim 1 including adjustable support means for said frame.

9. A projection system according to claim l wherein said series of apertures includes central aperture and a plurality of apertures arranged peripherally thereabout, and including an idler gear arrangement arranged in said central aperture for connection to said at least one gear whereby rotatable projectors disposed in said peripheral apertures may be driven by said idler gear.

10. A projection system according to claim 1 wherein said power supply means includes a transformer for selectively stepping down the voltage of said power supply.

11. A base according to claim 1 wherein said series of circular apertures is peripherally arranged in said planar member and said motor is mounted for movement toward and away from at least one said aperture. 

1. A projection system for planetaria comprising a base inclusive of a frame supportable on a supporting surface; a planar member on an upper portion of said frame having a series of apertures therein; a motor mounted in said frame having its shaft protruding above said planar member; at least one gear mounted on said shaft above said member; power supply means on said frame for said motor; a series of rotatable projectors selectively attachable to said base by telescoping in an aperture of said series of said apertures, and all projectors of said series of projectors having similar bases for insertion into an aperture of said series of apertures; gear means mounted on each projector of said series of projectors for rotative association with said at least one gear on said shaft for rotating each said projector concentrically about the aperture of said series of apertures in which said projector is mounted; and means for connecting the lamp of each projector to said power supply means.
 2. A projection system according to claim 1 including spring clamp means on said frame for temporarily securing projectors of said series of projectors thereon.
 3. A projection system according to claim 1 wherein a pair of gears are mounted on said shaft, one above the other, and each gear of said pair provides means for meshing with a gear on a projection of said series of projectors.
 4. A projection system according to claim 1 wherein the apertures of said apertures are spacedly arranged for mounting a projector of saId series of projectors in each aperture of said series of apertures at the same time.
 5. A projection system according to claim 1 wherein each aperture of said series of apertures is circular and said bases of said projectors are circular.
 6. A projection system according to claim 1 including outwardly directed flange means depending from each said projector for supporting said projector on said planar member.
 7. A projection system according to claim 6 wherein said outwardly directed flange means is an annular flange for seating on said planar surface.
 8. A projection system according to claim 1 including adjustable support means for said frame.
 9. A projection system according to claim 1 wherein said series of apertures includes central aperture and a plurality of apertures arranged peripherally thereabout, and including an idler gear arrangement arranged in said central aperture for connection to said at least one gear whereby rotatable projectors disposed in said peripheral apertures may be driven by said idler gear.
 10. A projection system according to claim 1 wherein said power supply means includes a transformer for selectively stepping down the voltage of said power supply.
 11. A base according to claim 1 wherein said series of circular apertures is peripherally arranged in said planar member and said motor is mounted for movement toward and away from at least one said aperture. 